27 April 2009 -- The current situation regarding
the outbreak of swine influenza A(H1N1) is evolving rapidly. As of 27
April 2009, the United States Government has reported 40 laboratory
confirmed human cases of swine influenza A(H1N1), with no deaths.
Mexico has reported 26 confirmed human cases of infection with the same
virus, including seven deaths. Canada has reported six cases, with no
deaths, while Spain has reported one case, with no deaths.

Further information on the situation will be available on the WHO website on a regular basis.

WHO
advises no restriction of regular travel or closure of borders. It is
considered prudent for people who are ill to delay international travel
and for people developing symptoms following international travel to
seek medical attention, in line with guidance from national authorities.

There
is also no risk of infection from this virus from consumption of
well-cooked pork and pork products. Individuals are advised to wash
hands thoroughly with soap and water on a regular basis and should seek
medical attention if they develop any symptoms of influenza-like
illness.

Related links

Interestingly enough WHO is not following its own description of pandemic phases -- based on its description, we are at phase 5. Until the swine flu affects another country outside of North America at a sustained level, the events won't be considered phase 6 (the Spanish case may not have any epidemiological connection to North America and an isolated case is not a sustained community level impact).

In nature, influenza viruses circulate
continuously among animals, especially birds. Even though such viruses
might theoretically develop into pandemic viruses, in Phase 1 no viruses circulating among animals have been reported to cause infections in humans.

In Phase 2 an animal
influenza virus circulating among domesticated or wild animals is known
to have caused infection in humans, and is therefore considered a
potential pandemic threat.

In Phase 3,
an animal or human-animal influenza reassortant virus has caused
sporadic cases or small clusters of disease in people, but has not
resulted in human-to-human transmission sufficient to sustain
community-level outbreaks. Limited human-to-human transmission may
occur under some circumstances, for example, when there is close
contact between an infected person and an unprotected caregiver.
However, limited transmission under such restricted circumstances does
not indicate that the virus has gained the level of transmissibility
among humans necessary to cause a pandemic.

Phase 4
is characterized by verified human-to-human transmission of an animal
or human-animal influenza reassortant virus able to cause
“community-level outbreaks.” The ability to cause sustained disease
outbreaks in a community marks a significant upwards shift in the risk
for a pandemic. Any country that suspects or has verified such an event
should urgently consult with WHO so that the situation can be jointly
assessed and a decision made by the affected country if implementation
of a rapid pandemic containment operation is warranted. Phase 4
indicates a significant increase in risk of a pandemic but does not
necessarily mean that a pandemic is a forgone conclusion.

Phase 5
is characterized by human-to-human spread of the virus into at least
two countries in one WHO region. While most countries will not be
affected at this stage, the declaration of Phase 5 is a strong signal
that a pandemic is imminent and that the time to finalize the
organization, communication, and implementation of the planned
mitigation measures is short.

Phase 6,
the pandemic phase, is characterized by community level outbreaks in at
least one other country in a different WHO region in addition to the
criteria defined in Phase 5. Designation of this phase will indicate that a global pandemic is under way.

During the post-peak period,
pandemic disease levels in most countries with adequate surveillance
will have dropped below peak observed levels. The post-peak period
signifies that pandemic activity appears to be decreasing; however, it
is uncertain if additional waves will occur and countries will need to
be prepared for a second wave.

Previous
pandemics have been characterized by waves of activity spread over
months. Once the level of disease activity drops, a critical
communications task will be to balance this information with the
possibility of another wave. Pandemic waves can be separated by months
and an immediate “at-ease” signal may be premature.

In the post-pandemic period,
influenza disease activity will have returned to levels normally seen
for seasonal influenza. It is expected that the pandemic virus will
behave as a seasonal influenza A virus. At this stage, it is important
to maintain surveillance and update pandemic preparedness and response
plans accordingly. An intensive phase of recovery and evaluation may be
required.

Human
cases of swine influenza A (H1N1) virus infection have been identified
in the United States. Human cases of swine influenza A (H1N1) virus
infection also have been identified internationally. The current U.S.
case count is provided below.

An investigation and response effort surrounding the outbreak of swine flu is ongoing.

CDC
is working very closely with officials in states where human cases of
swine influenza A (H1N1) have been identified, as well as with health
officials in Mexico, Canada and the World Health Organization. This
includes deploying staff domestically and internationally to provide
guidance and technical support.

CDC activated its
Emergency Operations Center to coordinate the agency's response to this
emerging health threat and yesterday the Secretary of the Department
Homeland Security, Janet Napolitano, declared a public health emergency
in the United States. This will allow funds to be released to support
the public health response. CDC's goals during this public health
emergency are to reduce transmission and illness severity, and provide
information to assist health care providers, public health officials
and the public in addressing the challenges posed by this newly
identified influenza virus. To this end, CDC has issued a number of
interim guidance documents in the past 24 hours. In addition, CDC's
Division of the Strategic National Stockpile (SNS) is releasing
one-quarter of its antiviral drugs, personal protective equipment, and
respiratory protection devices to help states respond to the outbreak.
Laboratory testing has found the swine influenza A (H1N1) virus
susceptible to the prescription antiviral drugs
oseltamivir and zanamivir. This is a rapidly evolving situation and CDC
will provide updated guidance and new information as it becomes
available.

Reasonably intelligent people could tell on Saturday morning that the appropriate pandemic level was Phase 4 (or even 5), that people should be advised not to travel to Mexico, California, and Texas, and I would argue that travel be stopped. And I can understand not saying anything until consultation occurred and measures were in place. But it appears to me that WHO, CDC, and the White House, were a day or two late in treating this situation as a genuine pandemic risk. I hope that we will not live (or die) to regret that delay. Obviously, the cat may have already been out of the bag as WHO argues, but I still think that closing borders would have been wise. Now, today WHO raised the level to phase 4, but says that closing the borders will no longer do any good given the spread to the U.S. and Canada. Apparently there are other countries reporting influenza like illnesses not yet confirmed as swine flu. But absent a spread outside North America, I still think that it make sense to close borders, even if only to delay the spread across these large countries.

Here's WHO's statement after the second meeting of the Emergency Committee today:

Statement by WHO Director-General, Dr Margaret Chan
27 April 2009

Swine influenza

The Emergency Committee, established in compliance with
the International Health Regulations (2005), held its second meeting on
27 April 2009.

The Committee considered available data on
confirmed outbreaks of A/H1N1 swine influenza in the United States of
America, Mexico, and Canada. The Committee also considered reports of
possible spread to additional countries.

On the advice of the Committee, the WHO Director-General decided on the following.

The Director-General has raised the level of influenza pandemic alert from the current phase 3 to phase 4.

The change to a higher phase of pandemic alert indicates that the
likelihood of a pandemic has increased, but not that a pandemic is
inevitable.

As further information becomes available, WHO
may decide to either revert to phase 3 or raise the level of alert to
another phase.

This decision was based primarily on
epidemiological data demonstrating human-to-human transmission and the
ability of the virus to cause community-level outbreaks.

Given the widespread presence of the virus, the Director-General
considered that containment of the outbreak is not feasible. The
current focus should be on mitigation measures.

The
Director-General recommended not to close borders and not to restrict
international travel. It was considered prudent for people who are ill
to delay international travel and for people developing symptoms
following international travel to seek medical attention.

The Director-General considered that production of seasonal influenza
vaccine should continue at this time, subject to re-evaluation as the
situation evolves. WHO will facilitate the process needed to develop a
vaccine effective against A/H1N1 virus.

The Director-General
stressed that all measures should conform with the purpose and scope of
the International Health Regulations.